The major objective of the Mouse Model Core is to provide a centralized service-oriented facility that offers the capability of producing and preserving transgenic and knockout mice. For the AADCRC program, the Core is specially charged with supporting the development of cell-specific and conditional expression strategies, particularly for targeting airway epithelial cells. The Mouse Core will also serve the projects of this program by supporting the infrastructure of a mouse model of respiratory virus infection and postviral asthma that will be extensively utilized by the projects. In that regard, the Core will oversee the use of standardized protocols of this model and ensure regulatory compliance with use of the protocol. Furthermore, in association with this model and other transgenic mouse models of experimental asthma, the Mouse Model Core will provide methods for measuring lung resistance and compliance for determinations of airway reactivity. Thus, the Mouse Core will be an important part of this AADCRC program. The major components of the Mouse Core, including the transgenic/knockout production unit and the respiratory infection unit are each provided with dedicated space and state-of-the-art equipment within our animal barrier facility. Moreover, the personnel that staff the Core have generally worked in it since its inception in 1995 and thereby have an extensive track record of productivity. Over this period, the Mouse Core has been responsible for generating over 120 transgenic and knockout mouse lines. The Mouse Core was an integral part of this AADCRC program during the previous funding cycle and was again highly productive in supporting each of the previous projects. For the next cycle, the Core is also central to the approach of each Project. In addition the Core has and will continue to provide a substrate for shared mice and phenotyping resources that serve to facilitate collaborative interactions among project investigators in the AADCRC program.